Questions on Algebra: Probability and statistics answered by real tutors!

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Question 581515: 2) The lifetimes of light bulbs of a particular type are normally distributed with a mean of 370 hours and a standard deviation of 5 hours. What percentage of bulbs has lifetimes that lie within 1 standard deviation of the mean on either side?
Click here to see answer by vmidick(1)

Question 599296: A health inspector must visit 4 of 9 restaurants on Monday. In how many ways can she pick the 4 restaurants?
Click here to see answer by jim_thompson5910(28598)

Question 599358: A container has 12 light bulbs, 4 of which are defective. Select 4 light bulbs. How many ways can we get 3 good and 1 bad light bulbs?
Click here to see answer by jim_thompson5910(28598)

Question 599354: Below is a probability distribution showing the year after purchase in which a certain brand of computer first fails:
Year- 1- 2- 3- 4- 5- 6 or more
Probability-.12-.02-.05-.08-.11-.62
(this means for example, that a computer that experiences its first failure in year 1 has failed in less than one year) A small business buys three of these computers. assuming that the three computers function independently, what is the probability that exactly two of the three computers will fail in less than three years?
Click here to see answer by stanbon(57377)

Question 599423: Four cards are drawn without replacement from pack of cards . What is the probability that (a) they all are of different suit .
(b) they all are aces.
Click here to see answer by stanbon(57377)

Question 599421: Find the chance of drawing a king , a queen , and a jack in that order from a pack of cards in three consucutive draws , the card drawn not being replaced
Click here to see answer by edjones(7569)

Question 599443: Find the probability of getting exactly three 5s if a die is rolled 5 times.
Click here to see answer by edjones(7569)

Question 599318: What is the probability that in ten independent tosses of a fair coin we get two heads in the first four tosses and five heads altogether?
Click here to see answer by richard1234(5390)

Question 599522:
Age Males Females
65-69 1.6 0.0
70-74 0.0 2.2
75-79 4.9 2.3
80-84 8.6 7.8
85+ 35.0 27.9
Prevalence of Alzheimer's disease (cases per 100 population)
Suppose an unrelated 77 year old man, 76 year old woman, and 82 year old woman are selected from the community.
What is the probability that all three of these individuals have Alzheimer’s?

Click here to see answer by stanbon(57377)

Question 599452: After a losing season, there is a great uproar to fire the head football coach. In a random sample of 250 college alumni, 105 favor keeping the coach. Test at the .01 level of significance whether the proportion of alumni who support the coach is less than 50 percent.
State the null hypothesis and the alternate hypothesis
State the decision rule for .01 significance level.
Compute the value of the test statistic
Click here to see answer by stanbon(57377)

Question 599532: it is thought that a normal population's mean is less than 75. To test this, a random sample of size 19 is drawn. THe sample mean is 73.5 and the sample standard deviation is 2.1. Find an approximate range for the p-value and state the conclusion. What would your range be if we had used a two-tail test?
Click here to see answer by stanbon(57377)

Question 599535: if the correlation between age and physial flexibility is -68 what does this mean? How would this correlation look on a scatter diagram? What general shape would it have?
Click here to see answer by stanbon(57377)

Question 599729: A civic group sells 1000 raffle tickets to raise $2500 for its namesake charity. First prize is $1000, second prize is $300, and third prize is $200. How much should the group charge for each ticket?
Click here to see answer by lynnlo(4164)

Question 599773: An arcade has 20 different arcade games. You want to play at least 14 of them. How many different combinations of arcade games can you play?
Click here to see answer by edjones(7569)

Question 599706: Perform a hypothesis test for the following problem. Use the same format as the hypothesis test worksheets.

An office building complex uses thousands of fluorescent light bulbs each year. The brand of bulb it currently uses has a mean life of 900 hours. A manufacturer claims that its new brand of bulbs, which cost the same as the brand the complex currently uses, has a mean life of more than 900 hours. The office building’s management has decided to purchase the new brand if, when tested, the evidence supports the manufacture’s claim at the 0.05 significance level. Suppose 64 bulbs were tested with the following results: x̅ = 920 hours, s = 80 hours. Will the office building management purchase the new brand of fluorescent bulbs?

Click here to see answer by stanbon(57377)

Question 599699: 2. There is adequate information in each of the following to decide whether to reject or fail to reject the null hypothesis. Carefully examine the statements; you should not have to perform any computations.
What is your decision and explain why.
a) Ho: μ = 120 Let α = 0.05. Data: x̅ = 130.1 for n = 100, P-value = 0.068
H1: μ ≠ 120

b) Ho: σ = 2.8 Let α = 0.01. Data: s = 3.1 for n = 55
H1: σ < 2.8

c) Ho: p = 0.68 Let α = 0.05. Data: p̂ = 0.69 for n = 32, test statistic z = 0.09095
H1: p > 0.68

Click here to see answer by stanbon(57377)

Question 599845: Textbook authors and publishers work very hard to minimize the number of errors in a textbook. However, some errors are unavoidable. Mr. J. A. Carmen, statistics editor, reports that the mean number of errors per chapter is 0.8. What is the probability that there are less than 2 errors in a particular chapter?
Click here to see answer by stanbon(57377)

Question 599968: Chebychev's Theorem:
Suppose the time needed to assemble a piece of furniture is not normally distributed and that the mean assembly time is 28 minutes. What is the value of the standard deviation if at lease 77% of the assembly times are between 24 and 32 minutes?
Click here to see answer by Edwin McCravy(8909)

Question 600295: A bag has green and yellow marbles. You pick two marbles from the bag without replacement. The probability that the first marble is yellow is 3/5, the probability of drawing 2 yellow marbles is 12/35. Find the probability that the second marble is yellow.
Click here to see answer by solver91311(16897)

Question 600383: On the Leapwell gymnastics team, 14 gymnasts compete on the balance beam, 12 compete on the uneven bars, and 9 compete on both the balance beam and the uneven bars. If 37 gymnasts compete on neither the balance beam nor the uneven bars, how many gymnasts are on the Leapwell team?
Click here to see answer by solver91311(16897)

Question 600420: The monthly utility bills are normally distributed with a mean value of $160 and a standard deviation of $25.
(a) Find the probability of having a utility bill between 120 and 180.
(b) Find the probability of having a utility bill less than $120.
(c) Find the probability of having a utility bill more than $210.
Click here to see answer by sniper619(1)

Question 600478: A card is selected from a deck of 52 playing cards. Find the probability of selecting

· a prime number under 10 given the card is a heart. (1 is not prime.)
· a diamond or heart given the card is red.
· a King, given that the card is not a spade.

*****Show step by step work. Give all solutions exactly in reduced fraction form.*****
Click here to see answer by stanbon(57377)

Question 600499: a) fair coin is tossed 100 times:
What is the probability of obtaining an odd number of heads? Explain?
I have tried (10 choose 2)/ sample space of 2^100 but this is not correct, Please help me on what I am supposed to do.
b) given that the total number of heads is odd, what is the probability that the last two tails tosses are tails?
Thanks
Click here to see answer by richard1234(5390)

Question 600527: Find the following binomial probabilities:
a. n=8, p=.25, P(x = 4)
b. n=16, p=.4, P(4≤ x ≤7)
c. n=11, p=.5, P(x > 8)
Click here to see answer by jim_thompson5910(28598)

Question 600644: A multiple choice exam contains 50 questions. Each question has 5 choices, one of which is correct. We are interested in knowing the probability guessing exactly 18 questions correctly.

(a) Is this a binomial experiment? Explain how you know.
(b) Use the correct formula to find the probability of guessing exactly 18 questions correctly out of the 50 questions. Show your calculations or explain how you found the probability
Click here to see answer by jim_thompson5910(28598)

Question 600690: Essay; show all work. A community 5K run will award $50 to the winner. 60 people enter the race, and they each pay an entry fee of $20. Assuming they are all equally likely to win, what is a fair price for the competition? Round to the nearest cent.
Click here to see answer by stanbon(57377)

Question 600709: I am trying to solve for P
The equation is p + Q = 1
My problem is p + 0.3 = 1
I am in a college Biology class and they threw some math problem to us at the end of the semester, and I haven't had math in over 10 years! Can you help?

Click here to see answer by rfer(12666)

Question 600795: Two integers (from 1 to 30, inclusive) are chosen by a random number generator on a computer. What is the probability that the same number is chosen twice?
Click here to see answer by stanbon(57377)

Question 600751: what is the probability of rolling an odd number ( number: 1,3,5,7,9,11.)
Click here to see answer by stanbon(57377)

Question 600719: what is the probability of tossing two number cubes labeled 1-6 and getting a sum of 5 or less
Click here to see answer by stanbon(57377)

Question 601044: Two cards are dealt from ordinary pack;
Event (A) : both cards are same suit
Event (B): both cards are red
(i) Which event is more likely.
I have attempted this part and I believe I am right in saying that b is more likely with a probability of 0.24509... and A is 0.0588....
(ii) Find the probability that the two cards are either both red or both from the same suit.
(iii) Use the definition of p(A given B) to calculate the probability that the two cards are from the same suit, given that they are both red.
I am struggling on parts two and three.
Thanks

Click here to see answer by jim_thompson5910(28598)

Question 601029: The probability that the children of a certain couple will have red hair is 0.223. If the couple were to have five children, what is the probability that exactly two of them will have red hair?
Click here to see answer by jim_thompson5910(28598)

Question 601051: 3. A division has 12 employees, 8 males and 4 females.
(a) (3 points) In how many ways can a committee of 6 members can be selected from out of these 12?
12c6 = 924 ways
(b) (3 points) Find the probability that a random committee contains all males?
P(6 males) = 8C6/12C6 = 28/924
(c) (3 points) Suppose that the committee should have one President which has to be a female and two ordinary members who must be males.
How many different committees are possible?
4 x 8 x 7 x 9 x 8 x 7 = 112896
are any of these correct?
Click here to see answer by jim_thompson5910(28598)

Question 601106: If a coin is tossed 2 times, then a standard 6-sided die is rolled 2 times, and finally a 5-card hand is drawn from a deck of cards, how many different outcomes are possible?
Click here to see answer by solver91311(16897)

Question 601154: A number from 17 to 26 is drawn at random. Find p. (An even number)
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Question 601158: A number from 9 to 15 is drawn at random. Find p (15, 9, 11, or 14)
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Question 601159: Bjorn is writing the 5 letters in his name in different orders. In how many different orders can he write the letters?
Click here to see answer by jim_thompson5910(28598)

Question 601212: I need help with the following problem:
in her wallet, anne has 14 bills, seven are $1 bills, two are $5 doller bills, four are $10 dollar bills and one is a $20 dollar bill. she decides to select one bill at random from her wallet. determine
A. the probaility she selects $5 dollar bill
B.the probablilty she does not select a $5 dollar bill
C. the odds in favor of her selecting a $5 dollar bill
D. the odds against her slecting a $5 dollar bill
Click here to see answer by stanbon(57377)

Question 601187: A fair die is rolled six times. Calculate the probability of obtaining exactly two 3s
Click here to see answer by stanbon(57377)

Question 601199: How do I answer this problem? 65-15>20-=
Click here to see answer by Alan3354(30993)

Question 601093: 4. X is normally distributed with mean 12 and standard deviation 4.
(a) (3 points)Find the probability that X will be more than 10.
p(X > 10) = 1 – p (X <= 10) = 0.69
(b) (3 points) Find the probability that X will be less than 13.5
P(X < 13.5) = P(X < = 13.5) = 0.646
(c) (4 points) Find the probability that X will be between 10 and 14.5
P(10 < X < 14.5) = P(X < 14.5) - P(X < 10) = P(X <= 14.5) - P(X <= 10) –
0.7340145 - 0.3085375
(d) (4 points) Find a such that P(X 0.85 = 85% is the quantile.
P(X < 16.14573) =
P(X <= 16.14573) = 0.85
(e)(4 points) Find b such that P(X> b)=.25
P(X > b) = 1 - P(X <= b) = 0.25
= > 1 - 0.25 - P(X <= b) = 0;
0.75 - P(X <= b) = 0
0.75 = P(X <= b);
P(X <= b) = 0.75.
= > P(X <= 14.69796) = 0.75.
Did I do these right?
Click here to see answer by jim_thompson5910(28598)

Question 601243: If Carla and Hannah are the 1st two winners to choose prizes from a treasure box, what is the probability that they both will pick plastic spiders? The box contains 21 stickers, 25 spiders, 3 key rings, and one $20 bill for a total of 50 prizes.
I think it's P(A X B) = Carla draws 1st which = 25/50 or 1/2
Hannah draws 2nd which = 25/49
answer = 25/98
Click here to see answer by jim_thompson5910(28598)

Question 601209: number 32 on 12-3 on the algebra 2 book for california
Click here to see answer by Alan3354(30993)

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